02 Photon Sources and Electron Accelerators
T25 Lasers
Paper Title Page
TUPMK008 Highly-stable, High-power Picosecond Laser Optically Synchronized to a UV Photocathode Laser for an ICS Hard X-ray Generation 1504
 
  • K.-H. Hong
    MIT, Cambridge, Massachusetts, USA
  • D. Gadonas, L.M. Hand, K. Neimontas, A. Senin, V. Sinkevicius
    Light Conversion, Vilnius, Lithuania
  • W.S. Graves, M.R. Holl, L.E. Malin, C. Zhang
    Arizona State University, Tempe, USA
  • S. Klingebiel, T. Metzger, K. Michel
    TRUMPF Scientific Lasers GmbH + Co. KG, Munchen-Unterfoehring, Germany
 
  Under the CXLS project at Arizona State University we are developing an inverse Compton scattering (ICS) hard X-ray source* towards a compact XFEL with electron nano-bunching. The ICS interaction is critically dependent on the quality of driver pulses such as: 1) available peak intensity, 2) energy/pointing stability, and 3) relative timing stability to UV pulses initially triggering electron beams. Here, we report on a highly stable, 1 kHz, 200 mJ, 1.1 ps, 1030 nm laser with good beam quality as an ICS driver, optically synchronized to a UV photocathode laser. The ICS driver is based on a Yb:YAG thin-disk regenerative amplifier (RGA), ensuring an excellent energy stability (shot-to-shot 0.52% rms; 0.14% rms over 24 hours). The pointing stability better than 4 urad is obtained. The M2 factor is as good as ~1.5 at the full energy, leading to the achievable laser intensity of >1017 W/cm2 with f/10 focusing. The photocathode laser, a frequency-quadrupled Yb:KGW RGA, share a common seed oscillator with the ICS driver for optical synchronization. The residual sub-ps timing drift is further reduced to 33 fs rms using an optical locking scheme based on a parametric amplifier.
* W.S. Graves et al., "Compact X-ray source based on burst mode inverse compton scattering at 100 kHz," Phys. Rev. ST Accel. Beams, Vol. 17, p. 120701 (Dec. 2014).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMK008  
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THPMF028 Coherent Stacking Scheme for Inverse-Compton Scattering at MHz Repetition Rates 4103
 
  • P. Piot, D. Mihalcea
    Northern Illinois University, DeKalb, Illinois, USA
  • T.J. Campese, A.Y. Murokh
    RadiaBeam Systems, Santa Monica, California, USA
  • D. Mihalcea, P. Piot, J. Ruan
    Fermilab, Batavia, Illinois, USA
 
  Funding: Work sponsored by the DNDO award 2015-DN-077-ARI094 to Northern Illinois University and US DOE contract DE-AC02-07CH11359 to Fermilab.
An experiment to produce 1-MeV gamma rays via Compton back-scattering of infrared photons on 250-MeV electron bunches is currently in preparation at the Fermilab Accelerator Science & Technology (FAST) facility. To increase the gamma-ray flux the energy of the infrared laser pulses are planned to be amplified within the interaction region using a resonant cavity. This passive amplifier composed of a Fabry-Perot cavity will allow the laser pulse bunches to coherently and constructively stack. Our estimates, based on theoretical models, show that the laser pulse energy can be increased from approximately 1-2 mJ at the exit of the last active amplifier to 5 -10 mJ at the interaction point when the laser repetition rate is set at the nominal value of 3 MHz. This paper details the cavity design option(s) and associated wave-optic simulations.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF028  
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THPMF072 Implementation of Ultra-Low Frequency Non-Linear Raman Spectroscopy with the Gun Laser at FLUTE 4242
 
  • S. Funkner, E. Bründermann, A.-S. Müller, M.J. Nasse, G. Niehues, T. Schmelzer, J.L. Steinmann, M. Yan
    KIT, Eggenstein-Leopoldshafen, Germany
  • M. Tani
    University of Fukui, Fukui, Japan
 
  At the Karlsruhe Institute of Technology (KIT) the new compact versatile linear accelerator FLUTE is currently under commissioning. This accelerator will provide intense broadband THz pulses for spectroscopic experiments. Here, we demonstrate the implementation of a coherent Raman spectrometer using the RF gun laser of FLUTE. With our experiment, we can measure the Raman spectrum at ultra-low frequencies. The measurement principle, which was recently published, is based on coherent nonlinear excitation of the observed sample. The spectrometer consists of a stretcher and an interferometer, which can be simply built from standard optics. We will show that the accessible spectral range overlaps well with that from the THz pulses of the planned FLUTE experiment. Thus, the coherent Raman experiment can provide spectral information complementary to absorption spectral measurements using the THz radiation of FLUTE.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF072  
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THPMK115 Optical Cavity R&D for Laser-Electron Interaction Applications 4587
SUSPF032   use link to see paper's listing under its alternate paper code  
 
  • X. Liu, W.-H. Huang, C.-X. Tang, L.X. Yan
    TUB, Beijing, People's Republic of China
  • R. Chiche, K. Dupraz, P. Favier, A. Martens, H. Monard, Z.F. Zomer
    LAL, Orsay, France
  • D. Nutarelli
    LAC, Orsay, France
 
  Laser-electron Inverse Compton Scattering X-ray source based on optical enhancement cavity is expected to produce higher-flux and better-quality X-rays than conventional sources, in addition, to become more compact, much cheaper than Free Electron Laser and Synchrotron Radiation. One X-ray source named ThomX is under construction at LAL, France. An electron storage ring with 50 MeV, 16.7 MHz electron beam will collide with a few picosecond pulsed laser to produce 1013 photons per second. A prototype cavity with a high finesse (F=25,100) in the picosecond regime is used to perform R & D for ThomX. We obtained 380 kW power stored in the optical cavity and mode instabilities were observed. The EOM-based frequency modulation to measure the finesse, the influence of dust on finesse, high-power experiments and other related issues are mentioned briefly. We will also describe the TTX2 (Tsinghua Thomson Scattering X-ray source) at Tsinghua University which is in design process. TTX2 prefers using an electron storage ring and an optical cavity in order to get high X-ray flux.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK115  
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